Sawdust-burner



(No Model.)

H. L. HI'LDRETH. SAWDUST BURNER.

NO. 409,285. Patented Aug. 20, 1889.

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llntTnn TaTns IiaTnNT @Trina HENRY L. IIILDRHII, OF SAGINAlV, MICHIGAN.

SAWDUST-BURNER.

SFECIFICATION forming part of Letters Patent No. 409,285, dated August20, 1889.

Application ledApril 17,1889. Serial. No. 307,541. (No model.)

T0 all whom t may] concern,.-

Be it known that I, HENRY L. .lIILDRETH, of Saginaw, county of Saginaw,and State of lllichigan, have invented an Improvement inSawdust-lurners, of which t-he following is a specification.

My invention relates to sawdust-burners; and it consists of certainimproven'lents, which are fully set forth in the :followingspecification and shown in the accompanying draw ings.

lleretofore it has been found difficult to construct 'a practicallysuccessful sawdustfurnace for the purpose of generating steam Ainsuflicient quantities for practical use and in an economical manner. Insawdnills and places where there is a large quantity of waste wood andsawdust it is highly desirable to utilize the sawdust and waste wood asfuel for the purpose of generating steam to run the mills. l'Vhile moreor less success has been obtained with the sawdust of soft wood-such aspine-it has been impossible to suceessfully utilize hemlock andhard-wood sawdust such as oak, elm, maple, ash, 85e.- from which asufficiently hot fire has not heretofore been obtained.

The object of my invention is to overcome this difficulty and to producea practically successful sawdust-furnace for burning any kind of sawdustand obtainingtherefrom sufficient heat for the generation of steam insufiieient quantities. This I accomplish by the construction andarrangement of my grate, whereby a large grate-surface is obtained, andby the employment of a forced draft through the grate, as is hereinaftermore fully described.

In the drawings, Figure l is a vertical sectional view of my improvedsawdust-burner, on an enlarged scale, through the line y/'jz/ of Fig. 2.Fig. 2 is a longitudinal sectional View through the line of Fig. l.Ifig. b is a perspective view ol' one of my improved gratcbars; and Fig.et isl a longitudinal sectional view of a sawdust-burner, illustrating amodified arrangement of the parts.

A are the walls of the furnace, in which the boiler B is supported inthe usual manner.

C is the smoke-stack.

I) is a wall or abutment to support the gratos.

E is the hearth.

F are the grate sections or bars, supported upon suitable supports a andd, located, respectively, on the front wall and on the abutment or wallI These grate sections or bars are formed, preferably, in the invertedbox or trough shape, as shown, having the upwardlyextending an dinwardly-1'nclinin walls F and the flat top G. These walls are providedwith perforations or holes f. I prefer, however, to Vform the forwardend walls and the top walls unperforated, as shown, to prevent cloggingof the grate and blowing of the flames and out through the furnace-door.

The object of forming the grate sections or bars lin the mannerdescribed is to obtain a larger and more effective grate-surface, and

it is apparent that the particular shape shown may be varied in manyways without departing from the principles of my invention. Thus, thewalls might be arched or Vshaped in cross-sections.

Il is a rim about the base of the grate section or bar, which is adaptedto fit closely against the walls of the furnace and the rim of theadjacent section. I prefer to construct one side of the rim with a ledgeor iiange I, which is adapted to lit over the rim of the adjacentsection to prevent a draft through any openings between the adjacentsections or bars.

Any number of sections may be used, arranged side by side, as shown,with theflanges I tting over the rims of the adjacent sections. The sideedges where the rims II come in contact with the walls A and D should beluted, preferably with fire-clay, as shown at Z. By this means and bytheflanges or ledges I the passage of air through the grate is entirelyprevented, except through the holes or perforations f.

K is a blower.

L is a pipe leading from the blower K and opening` under the grate. Iprefer to lead the air di reetly under each grate-section F by means ofbranch pipes M, with an extended grate-surface formed of a number ofgratesections. It is apparent that a number of boilers may be used.

The sawdust is introduced through a door or opening N, or in any otherconvenient I prefer to have the grate sections TOO or bars I" set low inthe tire-box, as thereby a large fuel-space is obtained. The sawdust isplaced through-the door II upon thc grate formed of the sections of thebars F, or, when a number of boilers are used, it may be introduced fromthe top between the boilers. By means of the blower K a draft is forcedthrough the holes or perforatious f and through the fuel, which iscaused thereby to burn with a great heat, the luting of the sides andends with fire-clay, as heretofore described, preventing the passage ofair except through the holes or perforations The products of combustionpass off through the stack C.

In Fig. 4 is shown a modification in which my improved burner isemployed in combination with the usual grate and lire-box. In this arrangement my improved sawdust-bu rning grate is arranged behind theordinary grate O and preferably slightly lower, so that the largerpieces of wood and lumber may be burned on the grate O, and the sawdustand smaller pieces falling upon the grate F will be there consumed inthe manner heretofore described.

While I prefer the details of construction here shown, I do not limit myinvention thereto, as it is apparent that they may be varied in manyways without departing from the principles of my invention.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a sawdust-burner, the combination, with the fire-box, of a gratefor the sawdust supported in said iire-box, having raised portionsprovided with holes or perforations, and having its edges in contactwith the sides of said fire-box luted to make a tight joint,substantially as and for the purpose specified.

2. In a sawdust-burner, the combination, with the fire-box, of a grateconsisting of a number of sections supported in the fire-box, saidsections being provided with raised perforated portions and overlappiu geach other on adjacent edges to form substantially airtight contact.

3. A grate-section for va sawdust-burner, consisting of a hollow boxadapted to be supported over the hearth and-having its bottom openthereto, provided with upwardly-inelining side walls and a dat top tosupport the fuel during combustion, and provided with holes orperforations in said side wall opening into the body of the fuelsupported upon the section, said section being closed to the passage ofair except through said holes, substantially as and for the purposespeciiied.

at. A grate-section for a sawdust-burner, consisting of a hollow boXhaving upwardlyinclining side walls and a flat top, holes orperforations in said side walls, and a rim or flange about the base ofsaid grate-section for the purpose of supporting it within the fireboX.

5. A grate-section fora sawdust-burn er, consisting of a hollow box,upwardly-inclining side walls, and a flat top, holes or p'erforations insaid side walls, a rim or flange about the base of said grate-sectionfor the purpose of supporting it within the nre-box, and a projectingledge upon one side of said rim 'or flange, adapted to it over the rimor flange of the adjacent grate, to form substantially air-tightconnection between them.

In testimony of which invention I hereunto set my hand.

HENRY L. HILDRETH.

Witnesses:

C. G. STEVENS, C. H. MCARTHUR.

